Switch



SWITCH July 1,21'930 J. R. cooK I 1,768,572

Filed Oct. 18'. 1928 Patented July 1, 1930 UNITED STATES PATENT OFFICE JOEL IR. COOK, F CLEVELAND, OHIO, ASSIGNOR TO RADIART LABORATORIES, INC., OF CLEVELAND, OHIO, A CORIPOIR'A'IIONV OF OHIO SWITCH Application led October 18, 1928.

This invention relates to electric switches, particularly those which are adapted for use in connection with portable devices, such as radio receiving sets. Where theradio receiving sets are operated by alternating current directly from the residence service line, provision must be made for obtaining uniform tube voltage, notwithstanding the fact that service line voltages vary in different 1 parts of the country. Where a switch is employed for interchanging the transformer connections depending upon the line voltage in any particular location, provision must be made for a switch which will minimize ,5 sparking of the contacts and at the same time will be suiiciently compact to be satisfactorily positioned within the restricted space of the radio cabinet.

In the present embodiment, a switch which controls the transformer connections, is mounted upon the outer surface of a transformer container which is known as a power-pack unit. When so used, an object of my invention is that the switch will prevent objectionable arcing, will be capable of easy and quick adjustment to secure the desired voltage, and will possess a small number of working parts.

A further object of my invention is to en- 31 close the contact members, and to make an indexing switch by means of which the registration of the contacting parts may be prop- -erly obtained even though such parts cannot be viewed by the operator.

Referring to the drawings, Fig. 1 shows a perspective view of a power pack unit embodying my invention; Fig. 2 is a section taken through Vthe switch on a plane indicated by the line 2--2 in Fig. 1; Fig. 3 is a section taken through the switch on a plane indicated by the line 3-3 in Fig. 2; c Figs. 4 and 5 are sectional views through the switch on planes indicated by the corre spondingly numbered lines `in Fig. 3, whlle Serial No. 313,217.

Fig. 6 is a perspective view of the contact arm which is used in connection with my switch.

The power-pack unit embodies a container 10 having a cover 11 upon which my switch indicated in general at 12 is mounted. For 5 convenience, a fuse compartment is also mounted upon the cover and is indicated in general at 13, while a scale 14 is shown directly beneath the switch. The present invention is not concerned with the electrical connections leading to the transformers, but is concerned primarily with the mechanical construction of the switch.

My switch, in the preferred form, comprises a structure which may be assembled, and then inserted as a unit within the cover, in the case of a power-pack, or upon a panel, in the case of any other electrical device, on which the switch is to be used. As exemplified in the power-pack, the switch has a base comprising a metallic strip 15, the ends of which, indicated at 16, are disposed behind the face 17 of the cover. The inwardly extending ends are utilized for holding the switch in place when the interior of the container is sealed with pitch. The base has rigidly mounted thereon adjacent the midportion thereof, a hollow stem 18 which is threaded to receive a retaining screw 19. The base is also shown as having pins 20 rigidly fastened thereto, and projecting in the same direction therefrom as the stem. The stem 18 functions to support the contact arm while the pins 20 serve as stops to limit the turning movement of the arm. The stem and pins also serve to hold two discs 21 and 22, of electrical insulating material, upon the base. The disc 21 occupies an opening 23 in the face of the cover, while the discl 22 carries spaced contact points 24, and an indexing contact plate 25. Connections 26 lead from the contact points 24 while a connection 27 leads from the contact plate 25 to the transformer (not shown) within the container l0.

The contact arm is shown upon an enlarged scale in Fig. G as comprising a metallic strip having an aperture 3l adjacent the mid-portion thereof and having upwardl v extending prongs 3Q adjacent the ends thereof. A strip ot electrical insulating niaterial 33 is placed over the contact strip 30, and is provided with tongues 34 and 85 which extend between the prongs 32 and are held in place by frictional engagement therewith. The tongue 35 projects through an opening 3G in the casing 37 and serves as a pointer tor the scale 14.

F rom the foregoing description, it will be evident that the contact plates are relatively stationary. and that the contact arm and casing 3T are relatively movable. Accordingly, the casing functions not to protect the operating parts only, but also to provide a knob which may be conveniently grasped in the fingers of the operator. A threaded member 19 holds the casing upon the stem and yet allows suilicient freedom for enabling it to be turned with reference to the stem. A spring is illustrated as surrounding the stem and as serving to force the contact arm into frictional engagement with the plate and contact points.

lVith this arrangement of contact arm and associated contact members, the relative position of such parts cannot be easily determined when the switch is operated. Accordingly, I provide an indexing mechanism by means of which the accurate registration of the arm with the respective spaced contact members can be readily obtained. Such indexing mechanism, in the preferred form, includes projections on the contact plate These projections are spaced in an arcuate path and the distance between them is such that one end ot the arm 30 ts snugly between adjacent projections, when the opposite end of the arm is in engagement with the contact members Q4. Since the spring :t0 tends to urge the arm against the contact members. it is obvious that the projections l5 tend to hold the arm against movement until the casing is manually turned.

A switch made in accordance with my invention advantageous, in that the operating parts are concealed, and yet, diiferent electrical connections can be satisfactorily made wit-hout objectionable sparking at the contact points. The switch parts are simple in construction, are principally stampings, and are held together by a single securing member. The simplicity of the switch, combined with its compactness of construction,

vmakes it suitable tor use in radio receiving bination, a base, a cont-act arm mounted thereon for movement with reference thereto, spaced contact members associated with the base and adapted to be engaged by the arm, one of said members having indexing means associated therewith, a casing enclosing the arm and said members, and means connecting the arm and casing for enabling them to be moved simultaneously with reference to the base.

2. An electric switch comprising in combination,` a relatively movable contact arm, a casing enclosing the arm and having an aperture therein, said arm having a portion thereof extending through the aperture, and providing a connection with the casing for enabling the arm to be turned simultaneously with the casing.

8. An electric switch comprising in combination, a base, a contact arm pivotally mounted thereon, spaced contact members associated with the base and mounted on one side of the pivotal connection for the arm, a contact plate associated with the base on the opposite side of the pivotal connection, said arm being adapted to engage the plate and members to provide an electrical connection therebetween, and means associated with the plate for indexing the arm with reference to the respective contact members.

Ll. An electric switch comprising in combination, a base, a contact arm pivotally mounted thereon, spaced contact members adapted to be progressively engaged by the arm as it is turned about the pivotal connection, a contact plate associated with the base and in constant engagement with the arm, indexing means associated with the plate for holding the arm in engagement with the respective contact members, a casing enclosing the contact arm and contact members, and means connecting the casing with the arm for effecting simultaneous movement of' the casing with relation to the base.

5. An electric switch, comprising in combination, a base, two members projecting from the base, a layer of electrical insulating material mounted on the base and being held in position thereon by said members, said layer having spaced contacts thereon, a contact arm pivotally mounted on one of said members and adapted to provide an electrical connection with some of said contacts, the other said members functioning to limit the turning movement of the arm, a casing enclosing the arm, members, contacts, and layer, said casing being mounted for turning movement with the arm and functioning as a knob for enabling the turning operation to be effected.

(3. An electrical switch comprising incombination, a base, a` hollow stem projecting therefrom, spaced contact members mounted on the base and adapted to be electrically connected by said arm, one of said members having pro'ections thereon arranged in an arcuate path, the projections being adapted to engage the arm for indexing it with reference to different contact members, a. casing enclosing the arm and members, and a spring surrounding the stem and engaging the easing and arm for holding the arm in frietional engagement with the Contact members, said casing being connected with the arm for turning movement therewith.

In testimony whereof, I hereunto aiX my signature.

JOEL R. COOK. 

